Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13, 11.4.x <= 11.4.3 fail to limit the size of the request body on the start meeting API endpoint, which allows an authenticated attacker to cause resource exhaustion or denial of service via a crafted oversized HTTP POST request to {{/api/v1/meetings}}.. Mattermost Advisory ID: MMSA-2026-00608

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Fixes

Solution

Update Mattermost to versions 11.6.0, 11.5.2, 10.11.14, 11.4.4 or higher.


Workaround

No workaround given by the vendor.

References
History

Mon, 18 May 2026 15:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Mon, 18 May 2026 09:45:00 +0000

Type Values Removed Values Added
First Time appeared Mattermost
Mattermost mattermost
Vendors & Products Mattermost
Mattermost mattermost

Mon, 18 May 2026 08:00:00 +0000

Type Values Removed Values Added
Description Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13, 11.4.x <= 11.4.3 fail to limit the size of the request body on the start meeting API endpoint, which allows an authenticated attacker to cause resource exhaustion or denial of service via a crafted oversized HTTP POST request to {{/api/v1/meetings}}.. Mattermost Advisory ID: MMSA-2026-00608
Title Improper Input Validation in MS Teams Meetings API Handler
Weaknesses CWE-770
References
Metrics cvssV3_1

{'score': 4.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: Mattermost

Published:

Updated: 2026-05-18T14:35:38.548Z

Reserved: 2026-02-11T00:04:25.542Z

Link: CVE-2026-2325

cve-icon Vulnrichment

Updated: 2026-05-18T14:35:34.131Z

cve-icon NVD

Status : Undergoing Analysis

Published: 2026-05-18T08:16:13.757

Modified: 2026-05-18T17:32:38.127

Link: CVE-2026-2325

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-05-18T09:30:22Z

Weaknesses